Analytical and experimental investigations of nanoparticles embedded phase change materials for cooling application in modern buildings

This paper presents the analytical and experimental investigations of the phase change heat transfer characteristics and thermodynamic behavior of spherically enclosed phase change material (PCM) with dispersion of nanoparticles for latent thermal energy storage (LTES) system in buildings. In this study, the heat transfer characteristics in terms of the transient temperature variations, moving interface positions, complete rate of solidification and melting were analyzed for the six different PCMs considered in pure form and with dispersed nanoparticles as well. The heat transfer characteristics of the PCMs considered were analytically modeled and experimentally evaluated for the steady state and transient conditions for various heat generation parameters during freezing and melting cycles of the LTES system. The experimental results infer that for the same thermal load conditions the rate of solidification for the PCMs decreased with the increased mass fractions of nanoparticles while compared to the pure PCMs. For the same operating conditions of the LTES system, similar heat transfer characteristics were observed for the six PCMs considered. In this paper, the analytical model solutions and experimental results for the 60% n-tetradecane: 40% n-hexadecane PCM are presented. The solidification time for the 60% n-tetradecane: 40% n-hexadecane PCM embedded with the aluminium and alumina nanoparticles were expected to reduce by 12.97% and 4.97% than at its pure form respectively. Besides, the test results indicate that by increasing the mass fraction of the nanoparticles beyond the limiting value of 0.07 the rate of solidification was not significant further. Furthermore, the rate of melting was improved significantly for the PCMs embedded with the dispersed nanoparticles than the pure PCMs. The analytical solutions obtained for the pure and dispersed nanoparticles based PCMs were validated using the experimental results. The deviations observed between the analytical solutions and the experimental results were in the range of 10%–13%. Based on the analytical and experimental results the present nanoencapsulated LTES system can be regarded as a potential substitute for the conventional LTES system in buildings for achieving enhanced heat transfer characteristics and energy efficiency.

[1]  S. Kalaiselvam,et al.  Energy efficient hybrid nanocomposite-based cool thermal storage air conditioning system for sustainable buildings , 2013 .

[2]  Transient natural convection heat transfer between concentric spheres , 1993 .

[3]  S. Iniyan,et al.  Experimental and analytical investigation of solidification and melting characteristics of PCMs inside cylindrical encapsulation , 2008 .

[4]  S. H. Choi,et al.  Thermal characteristics of paraffin in a spherical capsule during freezing and melting processes , 2000 .

[5]  Kamal Abdel Radi Ismail,et al.  A parametric study on ice formation inside a spherical capsule , 2003 .

[6]  W. Roetzel,et al.  Conceptions for heat transfer correlation of nanofluids , 2000 .

[7]  Wasim Saman,et al.  A phase change processor method for solving a one-dimensional phase change problem with convection boundary , 2010 .

[8]  Jean-Pierre Bédécarrats,et al.  Phase-change thermal energy storage using spherical capsules: performance of a test plant , 1996 .

[9]  Sih-Li Chen,et al.  An experimental investigation of cold storage in an encapsulated thermal storage tank , 2000 .

[10]  G. Domoto,et al.  Inward spherical solidification—solution by the method of strained coordinates , 1973 .

[11]  S. Kalaiselvam,et al.  Energy efficient PCM-based variable air volume air conditioning system for modern buildings , 2010 .

[12]  S. Kalaiselvam,et al.  Sustainable thermal energy storage technologies for buildings: A review , 2012 .

[13]  S. C. Solanki,et al.  An analysis of a packed bed latent heat thermal energy storage system using PCM capsules: Numerical investigation , 2009 .

[14]  E. H. Bishop,et al.  Natural convection heat transfer between concentric spheres , 1970 .

[15]  S. Iniyan,et al.  Phase change characteristic study of spherical PCMs in solar energy storage , 2009 .

[16]  K. Siva,et al.  Experimental and numerical investigation of phase change materials with finned encapsulation for energy-efficient buildings , 2010 .

[17]  J. Chung,et al.  Experimental investigation of condensation heat transfer in small arrays of PCM-filled spheres , 1991 .

[18]  A. Sari,et al.  Capric–myristic acid/expanded perlite composite as form-stable phase change material for latent heat thermal energy storage , 2008 .

[19]  Ruzhu Wang,et al.  A review on phase change cold storage in air-conditioning system: Materials and applications , 2013 .

[20]  M. Spiga,et al.  Discharge mode for encapsulated PCMs in storage tanks , 2003 .

[21]  E. Halawa,et al.  Thermal performance analysis of a phase change thermal storage unit for space heating , 2011 .

[22]  Latif M. Jiji,et al.  Analysis of solidification and melting of PCM with energy generation , 2006 .

[23]  Kamal Abdel Radi Ismail,et al.  Numerical and experimental study of spherical capsules packed bed latent heat storage system , 2002 .

[24]  James M. Hill,et al.  Freezing a saturated liquid inside a sphere , 1983 .